In vitro and in vivo release of dinalbuphine sebacate extended release formulation: Effect of the oil ratio on drug release.

Nalbuphine is a semi-synthetic opioid indicated for the relief of moderate to severe pain. Dinalbuphine sebacate (DNS) is a prodrug of nalbuphine for which we have developed long-acting lipophilic formulations in a benzyl benzoate/sesame oil mixture for intramuscular (IM) injection. In this study, we found that the in vitro release profile of DNS could be affected by adjusting the weight ratio of benzyl benzoate to sesame oil (the solvent/oil ratio). A longer release period could be attained by increasing the solvent/oil ratio in the formulation. A pharmacokinetic study was conducted in beagle dogs to verify the relationship between the in vitro release and the drug release from the formulations in vivo. The pharmacokinetic study confirmed that the formulation with a higher benzyl benzoate to oil ratio exhibits a longer drug release profile with a lower maximum concentration (Cmax) and a longer time to peak blood concentration level (Tmax) than the formulation with a lower benzyl benzoate to oil ratio.

Pharmacokinetics and protein binding of MPT0B292.

MPT0B292 was identified through screening of compounds able selectively to acetylate α-tubulins in cells and it exhibited potent anti-tumor, anti-angiogenesis and anti-metastatic effects in vitro and in vivo. Because of its poor water solubility, MPT0B292 is difficult to formulate with conventional approaches and hence difficulties are experienced in research practices. MPT0B292 was mixed with albumin in an aqueous solvent to form drug albumin nanoparticles with a size range around 333 nm. Unbound fractions of these nanoparticles were investigated in different or the same albumin concentration solutions. Unlike most drugs, the binding of MPT0B292 in human serum albumin increased with increasing drug concentrations. An analytical method was also developed and validated to determine MPT0B292 in rat plasma. This analytical method was applied successfully to the intravenous pharmacokinetic study of MPT0B292 in rats. A single dose study was regularly done to characterize the pharmacokinetic properties of the drug. Additionally, a novel i.v. infusion study was carried out to verify the extraction ratio of MPT0B292. The pharmacokinetic analysis revealed that MPT0B292 was a high extraction ratio drug with high systemic clearance, a high volume of distribution and a short half-life in rats. Copyright © 2017 John Wiley & Sons, Ltd.